How do I index?

[drizzle]

I am undercutting some transmission gears for a Honda motorcycle. I have a JET JDM18 mill and a Yuasa dividing head. I have an aluminum billet machined to hold the gear and the billet is held in my dividing head. How do I index each of the 5 dogs to the cutter so when I move the table left and right, I am getting a straight cut across the face of the dog? Current issue i have is, I have my dial test indicator held in a collet in the mill but it spins..... its not square to the table so my reading is off. I spend 10 minutes getting the face perfectly indicated in and when I looked down the side of the machine, the face was not parallel with the axis I was going to use to make my cut. I was off like 15 degrees. I am posting some reference pics from google for right now.

(Wont let me attach links to pictures)

If you notice, the dogs are pie shaped. When the gears are engaged, the dogs only mate about halfway down into the pockets so I can indicate down lower to get the most accurate reading. I just cant figure out how to get my indicator squared off of anything to get an accurate reading.

 

[drizzle]

http://www.psychobike.com/forums/attachments/suzuki-hayabusa/81841d1325983571-cut-trans-img_2622.jpg
https://ssli.ebayimg.com/images/g/NHgAAOSw-0xYNHPc/s-l1600.jpg
https://www.hayabusa.org/forum/attachments/shifter1stgear-jpg.1537401/
http://img.photobucket.com/albums/v356/Black_Bean/IMG_0338.jpg
https://www.orientexpress.com/images/Product/medium/20447.jpg

for those that dont know, when you shift a transmission with no clutch, it rounds off the corners of the dogs and creates a wedge shape which pushes the gears part under power. To repair this you resurface them to 90 degrees or undercut/back cut them with a dovetail cutter so that they stay locked in and the power load will suck them together, as seen here....
http://kawtriple.com/mraxl/trans_manual/undercut.jpg

 

[Mitch Alsup]

I am undercutting some transmission gears for a Honda motorcycle. I have a JET JDM18 mill and a Yuasa dividing head. I have an aluminum billet machined to hold the gear and the billet is held in my dividing head. How do I index each of the 5 dogs to the cutter so when I move the table left and right, I am getting a straight cut across the face of the dog?

Chuck (or collet) a DI or DTI in the spindle.
Hold gear to be machined in vise or fixture.
Adjust vise/fixture until you can traverse the gear on the table with the DI/DTI not showing any error during the traverse.

That is, the face of the gear gets trammed just like the vise gets trammed.

 

[drizzle]

I did that... I put the DTI in the collet BUT IT SPINS, HOW DO I SQUARE IT TO THE TABLE, If the indicator is on any sort of angle that is not 90 or 180 to the table, you get false readings. HOW DO I SQUARE IT?

 

[JimDawson]

As long as the indicator is more or less aligned to the axis you should be able to dial in the part to the desired travel axis. I normally put the head in back gear to keep the spindle from rotating. Normally there shouldn't be enough force on the indicator to even overcome the friction of the spindle. I guess it depends on what type of indicator you're using and how far the stylus is off of the spindle centerline. Normally I use a DTI for setups like this.

 

[drizzle]

I am using a DTI, there is resistance on the head but its belt drive so I cant keep change speeds, There is 2 bolts and an idler pulley that needs to be loosened with sockets/wrenches to change the belts. PITA. so doing the best I can do square it and leave it will work? I guess I can try that.

 

[JimDawson]

Can you post a picture of your setup? Using a DTI can not put enough force on the spindle to rotate it in any normal configuration, everything should be pretty close to the spindle centerline. I'm a little confused here.

 

[drizzle]

Sorry for the messy work place, its been work in progress. Just got mill wired up a week ago.

 

[drizzle]

also, I have no intentions of figuring out the math on the dividing head for this, I just want to indicate each face of the dog and cut it. I plan to use marker or dye on the faces and mesh with the corresponding gear to check for high spots and I will fine tune from there. I dont think that aspect of this has to be perfect, but cutting them even and retaining the pie shape of each dog is more critical. open to opinions.

 

[drizzle]

also, I used the marker as a referrence. its pretty much parallel with the table to show what I am trying to index/indicate in. i change the position of the gear in each picture.